Bromo-PEG8-bromide is a polyethylene glycol (PEG) derivative bearing terminal bromide groups. It is used as a bromo-functionalized linker for PEGylation, bioconjugation, and drug-delivery research; the bromide termini act as good leaving groups for nucleophilic substitution, facilitating attachment to thiols, amines, and synthesis of PEG-linked probes and linkers. Supplied for research use.